Find the recipient’s mobile carrier email-to-text gateway address
Format the message as an email addressed to the phone number at the carrier gateway
Use the person’s 10-digit phone number without spaces or punctuation
Add the carrier domain after the phone number
Keep the subject line short or leave it blank
Keep the message brief to fit SMS limits
Send the email from your normal email account
Wait for the message to arrive as a text on the phone
If the carrier is unknown, ask the recipient for their carrier
If the carrier supports MMS, use the MMS gateway for longer messages or attachments